What is a P800 tax calculation?​

What to do if you receive a P800

If a P800 drops through your letterbox or lands in your HMRC online account, it’s important to read it carefully. It could mean you’re owed money or that HMRC plans to adjust your tax. Here’s what to do next:

1. Read it thoroughly — Check which tax year it covers and what HMRC says about your income and tax paid.
2. Check the figures — Mistakes can happen. Make sure your income, tax code and employment details look right.
3. Follow the refund link — If the P800 says you’re due a refund, HMRC will usually include instructions to claim it online.
4. Don’t panic if you owe tax — HMRC usually collects underpaid tax by adjusting your tax code for the next year. You won’t be asked to pay a lump sum out of nowhere.

If anything’s unclear or doesn’t add up, RIFT’s here to help. We’ll explain what your P800 means, check the numbers for you, and make sure you don’t miss out on money you’re owed.

P800 Tax RefundCan you get a tax rebate without a P800?

In short, yes! A P800 is only sent when HMRC spots something unsual in your tax, but they don't catch everything. Many people are owed money without ever getting sent a P800. If you're waiting on HMRC to tell you, you could be missing out. You might still be owed a tax refund for:

• Mileage and travel costs for work
• Uniform, tools or equipment you've paid for yourself
• Gaps between jobs or periods on the wrong tax code

That’s why you need to keep records and claim your tax rebate each year—particularly if your job involves a lot of time on the road. Construction and Armed Forces work, for example, can mean a lot of mileage. If you’re not claiming back the tax you’re owed, you’re probably paying hundreds of pounds too much each year to the taxman! So, if you haven't had a P800 but think you've overpaid, don't wait. RIFT can check everything for you, even if HMRC hasn't been in touch.

My P800 says I'm owed a tax rebate, when will I get it?

If your P800 form says that HMRC’s going to send you a cheque, then within about 2 weeks of the date on the calculation they sent you, you should have your P800 refund in your hands. When HMRC decides to handle your refund this way, you can’t choose to get your money by bank transfer instead. Because of this, it’s essential that you make sure they have the correct address for you.

If your tax calculation says you need to claim your P800 refund online, then you’ve got a few things to take care of before you get your money. You can do it:

• Via HMRC’s online bank transfer service. You’ll need your P800 and proof of your identity to do this. You should have your refund within 5 working days.
• On the HMRC app, where you can ask for your refund as a bank transfer.
• By logging into your Personal Tax Account on the HMRC website. Again, you can get a bank transfer this way.
• By phoning HMRC and asking them to send you a cheque. P800 refunds claimed this way generally arrive within 6 weeks.

What if I didn't get a P800 but think I'm owed tax?

You could still be due a refund. HMRC only sends a P800 if they spot an issue, but that doesn’t mean they catch everything. If you’ve changed jobs, used your own tools or paid for work travel, it’s worth getting it checked.

Is a P800 always correct and what should I do if I think it's wrong?

Not always. While HMRC aims to be accurate, errors can happen, especially if they’re missing information about job changes, expenses or benefits. It’s always worth double-checking your P800 against your P60, P45 or P11D. Make sure HMRC hasn't used any estimates in the calculations. They use estimated figures sometimes if they don't have all the information they need to work out tax you owe.

If you’re getting any taxable state benefits, you’ll also want to compare HMRC’s figures with your own records. There’s a chance that some of those types of income will be lumped together as a single, combined total. If the number doesn’t look right, you should be able to get a full breakdown from HMRC or by checking your Personal Tax Account.

When you’ve arranged to pay through the PAYE system for any otherwise untaxed income, (like rent, for instance, if you’re letting out property), you might find HMRC has used estimated figures to calculate your tax. This can mean your PAYE tax code changes, and might not change back when you stop getting that income. Check the numbers HMRC has been working from, and kick up a fuss if they’re wrong.

At the same time, it’s worth putting some thought into anything HMRC might have missed. The taxman can only work with the information he has, and might not be up to date on things like:

• Any Gift Aid donations you might have made.
• Any contributions you’ve put into your pension.
• Your taxable state benefits and savings income.
• Any deductions or employment expenses you’re allowed to claim for, such as business use of your own vehicle.

While you’re at it, check that you’re getting the proper benefit from things like the Marriage Allowance or Blind Person’s Allowance, if you and/or your spouse qualify for them.

Equally, you have to keep in mind any allowances HMRC has included in their calculation that you might not qualify for any more. Again, these might have led to a change in your tax code at some point, so check everything’s been recorded correctly.

One more tricky little wrinkle that might complicate your P800 calculation is if you’re paid weekly. Basically, the way the calendar shakes out, some years might see you being paid 53 times instead of 52. Depending on your employer, that extra week’s pay might still factor your standard Personal Allowance into it, meaning you get a week’s tax relief that you technically didn’t qualify for over the year. Check your P60 to see if there’s a ‘week 53 indicator’ listed.

Once you've checked over it carefully and you still think it looks wrong, contact HMRC as soon as possible.

What's the difference between a P800 and a tax return?

A P800 is a calculation HMRC sends to some PAYE workers. A tax return (or Self Assessment) is something you fill in yourself, usually if you’re self-employed or have other untaxed income. They’re separate processes, but both affect your tax.